Eldorado - Repositorium der TU Dortmund

Ressourcen aus und für Forschung, Lehre und Studium

Bei diesem Service handelt es sich um das Institutionelle Repositorium der Technischen Universität Dortmund. Hier werden Ressourcen aus und für Lehre, Studium und Forschung gespeichert, erschlossen und der Öffentlichkeit zugänglich gemacht.

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Fach- und Universitätsübergreifendes 1319
Fakultäten 13766
Graduate School und Graduiertenkollegs 12
Hochschulverwaltung 1243
Sonderforschungsbereiche 1592

Aktuellste Veröffentlichungen

Beam monitoring at the Large Hadron Collider beauty experiment
(2026) Rolf, David; Albrecht, Johannes; Elsässer, Dominik
In particle physics, accelerators and detectors are continually improved to enhance the precision and functionality of experiments. An important part is to continue to ensure the safety of the experiment under the new conditions. The Large Hadron Collider beauty (LHCb) detector was upgraded for the data-taking period beginning in 2022. As part of the upgrade, the Beam Conditions Monitor (BCM), the safety system of the LHCb experiment, got new readout hardware: the Machine Interface Beam Abort Decision system. In addition, a new detector is planned to enhance the beam-monitoring capabilities at the experiment. The Timepix4 telescope is used as a prototype for this detector. In this work, the control system of both detectors is fully implemented. For the BCM, the focus is on the integration of the new MIBAD system, operating since June 2023. For the Timepix4 telescope, the focus is on the reusability of the components for the future beam-monitoring detector. Finally, beam losses are studied, which can damage the LHCb detector and contribute to a machine-induced background. The losses are characterised, and the contribution to the physics operations is discussed.
First demonstration of echo-enabled harmonic generation in a storage ring and deep learning for beam diagnostics
(2026) Krishnan, Arjun Radha; Khan, Shaukat; Tolan, Metin
The generation and characterization of ultrashort, coherent radiation pulses in the extreme ultraviolet (EUV) and X-ray regimes are critical for investigating ultrafast dynamic processes in matter. This thesis advances these capabilities through two complementary research directions: the development of deep-learning-based methods for advanced beam diagnostics and the first experimental implementation of echo-enabled harmonic generation (EEHG) in an electron storage ring. To overcome the limitations of conventional diagnostics, deep-learning-based methods were developed for both storage ring and free-electron laser (FEL) applications. At the 1.5-GeV electron storage ring DELTA, operated by the Center for Synchrotron Radiation of TU Dortmund University, coherent harmonic generation (CHG) is employed, a technique where an external laser seed interacts with the electron beam to generate ultrashort radiation pulses at harmonics of the laser frequency. A convolutional neural network (CNN) was trained to extract the spectral phase properties of the seed laser pulses from the CHG radiation spectra. This method successfully identified a large uncompensated third-order dispersion in the seed pulse, explaining previously unresolved spectral asymmetries. Furthermore, two CNN-based methods were implemented to reconstruct photon pulse profiles from longitudinal electron phase space images at FLASH, an FEL in Hamburg. This work involved the application of a standard U-Net model and a specialized dual-input design (Y-Net) developed specifically for this task. The deep learning models demonstrate the capability to perform single-shot reconstruction of the photon pulse profiles without requiring frequent reference measurements and reduce non-physical artifacts. In the experimental domain, this work presents the commissioning of the SPEED (Short Pulse Emission via Echo at DELTA) facility at DELTA. This project utilizes the EEHG mechanism that employs a two-stage seeding scheme to manipulate electrons in the longitudinal phase space for harmonic generation. By reconfiguring a 4.75 m electromagnetic undulator, the world’s first proof-of-principle demonstration of EEHG in a storage ring was achieved. Coherent emission was successfully observed and characterized up to the 11th harmonic (73 nm) of an 800 nm seed laser. These results confirm the robustness of the EEHG mechanism in a circular accelerator. Building on this success, a conceptual design for an optimized and compact permanent-magnet-based EEHG setup is presented. Simulation studies indicate that this design, fitting within a typical 5-meter straight section, can extend efficient harmonic generation up to the 29th harmonic (≈ 27 nm), showing a path forward for future short-pulse sources based on electron storage rings.
Sustainable, resilient, circular, degrowth, or smart?
(2025) Wood, Katharina Louisa; Gunzenhäuser, Randi; Gurr, Jens
This dissertation examines how the material dimension of green transformations – the built environment – both reflects and shapes cultural and social dynamics. It explores how architects, planners, and builders define ‘green’ design and how these definitions produce differing values and understandings of ‘greenness.’ Five conceptual scripts of greenness – (1) three-pillar sustainability, (2) resilience, (3) circularity, (4) degrowth, and (5) the smart city – serve as analytical lenses in this study. These scripts are understood as both narrative and technical frameworks that structure environmental meaning within urban space. Drawing on case studies from the Ruhr region (Germany) and the Atlanta metropolitan region (USA) – including the Kreislaufhaus, Tiny Houses Dortmund-Sölde, Essen 51, Mercedes-Benz Stadium, the Kendeda Building, and Roosevelt Hall – the research examines diverse approaches to sustainable architecture across contrasting urban contexts. Green building standards such as LEED, DGNB, and the Living Building Challenge (LBC) define criteria for energy efficiency, material sustainability, and occupant well-being, and thus function as key instruments for assessing and guiding ecological design practices. Using these standards alongside the concept of green scripts as a theoretical framework – and combining interviews, planning documents, and fieldwork – the study interprets green buildings as cultural artifacts within the transdisciplinary field of urban studies. The findings indicate that dominant green building standards emphasize engineering resilience features like stormwater management, energy independence, and structural durability over the social script of sustainability, often sidelining equity, accessibility, and collective well-being. The dissertation ultimately calls for deeper collaboration and dialog between engineering and cultural studies in standardization processes, as the built environment encodes key socio-political visions of sustainable futures.
Mehrebenen-Analyse der nachhaltigen und kreislaufwirtschaftlichen Transformation der deutschen Automobilindustrie
(2025) Isopp, Antonio Gennaro; Weyer, Johannes; Schubert, Cornelius
Diese Dissertation analysiert die nachhaltige und kreislaufwirtschaftliche Transformation der deutschen Automobilindustrie. Als Schlüsselbranche ist sie sowohl für die wirtschaftliche Leistungsfähigkeit Deutschlands als auch für die Erreichung nationaler Nachhaltigkeitsziele zentral. Der Übergang vom Verbrennungsmotor zu batteriebetriebenen Antrieben erfordert tiefgreifende organisationale Anpassungen etablierter Unternehmen. Im Mittelpunkt steht die Entwicklung und Anwendung eines methodischen Ansatzes zur Quantifizierung qualitativer Daten, um Transformationsfortschritte messbar und vergleichbar zu machen. Auf Basis der Multi-Level-Perspective und des Modells Multipler Sozialer Systeme wurde das Multi-Level Transformation-Process Model (MLTP) entwickelt, das innerorganisationale Dynamiken mit externen Einflüssen verknüpft. Die Ergebnisse zeigen einen insgesamt moderaten Transformationsstand. Fortschritte sind vor allem in der Regulierung im Zuge der Elektrifizierung erkennbar, während Infrastruktur und Technologie zurückbleiben. Die Methodik erweist sich als geeignet zur systematischen Erfassung von Transformationsprozessen, ergänzt jedoch qualitative Analysen. Da zentrale Annahmen nur teilweise bestätigt wurden, wird eine theoretische Weiterentwicklung des MLTP unter Einbezug der Theory of Planned Behavior empfohlen. Die Arbeit leistet einen methodischen und theoretischen Beitrag zur Transformationsforschung und bietet praxisrelevante Implikationen für Unternehmen und regulatorische Akteure.
Essays on non-GAAP measures and corporate governance mechanism
(2026) Freches, Fabian; Pott, Christiane; Kreße, Bernhard
This dissertation examines non-GAAP measures and corporate governance mechanisms from a multifaceted perspective. In capital markets characterized by information asymmetries, companies complement mandatory reporting with voluntary disclosures such as non-GAAP measures. While these measures may provide decision-useful insights, they may also be used opportunistically, raising questions of transparency and credibility. The dissertation comprises four studies on recent regulatory developments, investor perception, gatekeeping, and mandatory governance reporting. The first study conceptually analyzes Management Performance Measures (MPMs), a concept of non-GAAP measure proposed in the Exposure Draft (ED/2019/7), and contrasts them with existing frameworks, showing substantial alignment with existing regulations and only minor innovations. The second study experimentally examines perceived reporting reliability among professional and non-professional investors in Germany and finds that non-professional investors perceive reports including non-GAAP measures as more reliable, while professional investors remain largely unaffected. The third study examines analysts as capital market gatekeepers for non-professional investors and provides experimental evidence that non-GAAP measures may increase investment judgment, while analysts’ gatekeeping role is especially crucial in cases of opportunistic and non-transparent non-GAAP reporting. The fourth study uses a descriptive text analysis (pre–post) of remuneration reports under ARUG II and documents a substantial increase in report scope but only a slight decline in readability; nevertheless, remuneration reports remain complex overall. Overall, the dissertation contributes to a better understanding of the interdependencies between regulation, disclosure practices, gatekeepers, and investor responses in non-GAAP settings and related governance reporting.